|
Theorem : Vertical angles are always equal in measure.
Proof : To prove m Ð AOC = m Ð
BOD
m Ð AOC + m Ð COB = 1800 ( supplementary angles )
m Ð BOD + m Ð COB = 1800 ( supplementary angles )
i.e. m Ð AOC + m Ð COB = m Ð BOD + m Ð COB
or m Ð AOC = m Ð BOD.
Example 1
Measures of some angles are given below. Find the measures of their supplements.
a) 750 b) 1250 c) x0 d) (180 - x) 0 e) (90 + x) 0
Solution :
a) 1050
b) 550
c) (180 - x) 0
d) x0
e) (90 - x) 0
|
